1. Field
This patent specification relates to a method and apparatus for image communications, and more particularly to a method and apparatus for image communications capable of effectively performing a receipt acknowledgement.
2. Description of Related Art
Conventionally, facsimile communications are performed through communications networks including a PSTN (public switched telephone network) and an ISDN (integrated services digital network). However, as the Internet is coming into wide use in recent years, it becomes possible for facsimile communications to use the Internet. The facsimile communications using the Internet is referred to as an Internet-facsimile. The Internet-facsimile is an attempt to provide a facsimile transmission at a lower communications charge.
Since a method of transmitting image data using E-mail is standardized as a store-and-forward Internet-facsimile (abbreviated as an S&F Internet-Fax) according to RFC2305/2532 and T.37, the number of communications apparatuses supporting this method has grown recently. The above-mentioned term RFC stands for a request for comments and is published by the IETF (Internet engineering task force) which is an expert group for Internet engineering. The above-mentioned term T.37 is a name of a work group belonging to the CCITT (the International Telegraph and Telephone Consultative Committee).
The above-mentioned method for image communications provides a receipt acknowledgement feature in which a sender can request that a receiver send back a receipt acknowledgement. If the receiver supports this receipt acknowledgement feature, the receiver generates and returns an acknowledgement mail to the sender upon receipt of the request.
However, this method for image communications has a drawback, that is, it may be difficult for the sender to identify each receipt acknowledgement against the number of mails the sender has sent. This is because the sender cannot receive receipt acknowledgement as a real-time response from the receiver since each receipt acknowledgement from the receiver reaches the sender after a delay.